In browsers, the top-level scope is the global scope. That means that in
browsers if you're in the global scope var something will define a global
variable. In Node this is different. The top-level scope is not the global
scope; var something inside a Node module will be local to that module.

Deprecated In the past, this list has been used to load
non-JavaScript modules into Node by compiling them on-demand.
However, in practice, there are much better ways to do this, such as
loading modules via some other Node program, or compiling them to
JavaScript ahead of time.

Since the Module system is locked, this feature will probably never go
away. However, it may have subtle bugs and complexities that are best
left untouched.

The filename of the code being executed. This is the resolved absolute path
of this code file. For a main program this is not necessarily the same
filename used in the command line. The value inside a module is the path
to that module file.

Run callback cb repeatedly every ms milliseconds. Note that the actual
interval may vary, depending on external factors like OS timer granularity and
system load. It's never less than ms but it may be longer.

The interval must be in the range of 1-2,147,483,647 inclusive. If the value is
outside that range, it's changed to 1 millisecond. Broadly speaking, a timer
cannot span more than 24.8 days.